Return bend for cracking stills



Dec. 17,1935. H. c. STOCKHAM 2,024,399

I RETURN BENDIFOR CRACKING STILL Filed March 14, 1932 FIG. FIG. 2.

INVENTOR /?ATTORNEY Patented Dec. 17, 1935 RETURN BEND Foa caacxmc s'rmLs Herbert G. Stockham, Birmingham, Ala, assignor to Fred C. Fantz, Webster Groves, Mo.

- Application March 14, 1932, Serial No. 598,648

3 Claims. '(01. 285-20) My invention relates to that class of 'return' bends which are used in refinery apparatus, such as oil cracking stills, where the tubes are located in nests or banks and must be provided with. con- I nectionson their ends so as to ensure an uninterrupted flow of the liquid from one tube to its next adjacent tube and to provide an uninterrupted surface.

It is well known that the high pressure and 10 temperature sometimes causes these tubes to warp so that it is essential to provide some means to hold the tubes in position, when the return bend has been removed for the purpose of cleaning the tube of the coke which deposits rapidly 15 on their interior when the still is in operation,

also for the purpose of permitting inspection of the tubes or the removal of a damaged tube.

This is best accomplished by making a unitaryhousing in which the return bend is mounted. 20 In a device of this character it is essential that means be-provided for the convenient removal of the return bend and also convenient replacement of the tubes.

My invention is designed as an improvement 25 upon the device shown in Patent No. 1,831,709. My invention has for its object to provide an improved joint. As 'shown in-the patent referred to, the joint is formed on the collar or bushing which is screwed on to the end of the still tube. 30 My invention is designed to provide for the joint on the end of the tube itself so that the pressure exerted to tighten the joint will be entirely for compression.

A further object is to avoid the necessity of 35 having to roll the tube into the threads to .render them gas tight.

My means of accomplishing the foregoing objects may be more readily understood by having reference to the accompanying drawing which is hereunto annexed and made a part hereof, in

which Fig. 1 is a side elevation, one-half of the housing being broken away and the part shown in section, fragmentary portions only of the: tube being shown-as my invention is only concerned with the ends of the tubes;

Fig. 2 is a vertical section through one of the tubes housing and return bend; and

Fig. 3 is a top or plan view, one-half of the re'...rn bend being broken away and the securing means being omitted so as to show the interior construction of the housing.

Similar reference numerals refer to similar parts throughout the entire description. 55 As shown in the drawing my invention comprises a return bend l which is designed to con- "nect still tubes 2 and 3. As the joint between the t bes 2 and 3v and the face 'of the return bendi ar identical I shall only describe a. single joint and its component parts.

The return bend l is mounted in a housing 1. which consists of two annular members .5 and 6. These members are connected by a web or webs 1. Each of the members 5 and'G are provided with upwardly extending arcuate side walls 8 and 10 9, the exterior which is preferably polygonal to facilitate closer nesting of the tubes.

The walls 8 and 9 are provided withslots In and II adjacent their upper ends in which are mounted plates I2. Each of the plates l2 carries a set screw I3, the inner end of which bears against an abutment I4, cast or formed, on the exterior wall of the return bend l.= Each face l5 of the return bend l is provided with an 'annular V shaped groove it which is fitted to an upwardly projecting annular ridge I! which is convex in cross section and is adapted to flt the grooves l6 forming a linecontact. This ridge projects from the end' of the still tubes.

The ends of the tubes 2 and 3 are provided with threads I8 upon which is screwed a collar l9 which is provided with external shoulders 20 adapted to interlock with shoulders 2| formed on the internal surface of the'openings in the annular. members 5 and 6 of the housing.

It will be apparent to persons skilled in the art that the collar I9 is screwed on the tube only for the purpose of keeping it from pulling out from the annular members 5 and 6.

The device is assembled'as follows: The housing is first slipped over the tubes .2 and 3, the tubes passing through the openings in the annular members when the collars I! are screwed on to the threads l8this may be done in any convenient or suitable manner by socket member 5 spanner for example.

The return bend l is then placed in the housing, the grooves IS in the faces of the return bend engaging the annular ridges I! on the ends of the tubes. The plates I! are then placed in. position and the set screws l3 tightened up. This serves to draw the tubes into tight engagement with the return bend.

It will be apparent from the foregoing description that the collar l9, fitting as it does into the annular members, serves to hold the tubes 2 and 3 in spaced relation to each other so that it is impossible. for themto spring apart when the return bend is removed for the purpose of cleaning etc. Although I haveshown the colthe pressure and temperatures are resisted by the compression of the return bend upon the end of the tube rather than upon the end of the collar. This tends to ensure the maintenance of a leak-proof joint which is highly essential in devices of this character. For the purpose of complete disclosure of a concrete device, I have described with some degree of particularity a type of joint but it is obvious that any desired type may be employed.

Having described my invention what I regard as new and desire to secure by Letters Patent is:

1. In a high pressure refinery apparatus, a conventional return bend adapted to connect a pair of adjacent still tubes, to provide a continuous passageway therethrough, a hexagonal shouldered collar continuous in cross section secured adjacent the ends of each tube, the end of the tube projecting through said collar, a'

housing member comprising annular portions having hexagonal openings therethr ough, the

walls of which are adapted to abut the shoulders on the collar and means carried by the housing to draw the face of the bend and the ends of the tubes into a leak-proof joint.

2. In a high pressure refinery apparatus, a

' conventional'return bend adapted to connect a 5 pair of adjacent still tubes, to provide a continuous passageway therethrough, a polygonal shouldered collar continuous in cross section secured adjacent the ends of each tube, the end of the tube projecting through said collar, a housing member comprising annular portions having polygonal openings therethrough, the walls of which are adapted to abut the shoulders on the collar and means carried by the housing to draw the face of the bend and the ends of the tubes into a leak-proof joint.

3. In a high pressure refinery apparatus, a conventional return bend adapted to connect a pair of adjacent still tubes, to provide a continuous passageway therethrough, a hexagonal shouldered collar continuous in cross section secured adjacent the ends of each tube, the end of the tube projecting through said collar, a housing member. comprising annular portions having hexagonal openings therethrough, the walls of which are adapted to abut the shoulders on the collar and means carried by the housing to draw the face of the bend and the ends of the tubes into a leak-proof joint, the outer walls of which are hexagonal in cross section whereby closer nesting of the tubes is attained.-

; HERBERT C. STOCKHAM. 

